Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment, as examples. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductive layers of material over a semiconductor substrate, and patterning the various material layers using lithography to form circuit components and elements thereon.
Shallow trench isolations (STIs) are commonly used in the fabrication of semiconductor devices to isolate active regions of the semiconductor substrate and/or prevent electrical current leakage between adjacent devices. In STI, one or more trenches may be etched into a surface of the substrate and then filled with a dielectric material, such as silicon dioxide. The dielectric material may help to reduce electrical current leakage between adjacent semiconductor devices within the same trench or across different trenches.
Due to the huge numbers of devices that are present on a semiconductor substrate and the continual increase in the integration density of various electronic components (e.g., transistors, diodes, resistors, capacitors, etc.) by continual reductions in minimum feature size, the space between the devices is getting narrower. Because of this, isolation of the devices from each other is becoming increasingly difficult.